//
//  Atom.h
//  1.-4-5 OC
//
//  Created by 钟纪旺 on 16/4/5.
//  Copyright © 2016年 zjw. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface Atom : NSObject

@property (readonly) NSUInteger protons;
//等于结构体里面的变量 property 
@property (readonly) NSUInteger neutrons;
@property (readonly) NSUInteger electrons;
@property (readonly) NSString * chemicalElement;

- (NSUInteger) massNumber;

@end
